Hardware Load Balancer Requirements

Enterprise Edition Lync Front End Server pools will require a Hardware Load Balancer (HLB) to be deployed to provide high-availability to the web services for that pool. In Lync Server 2010, introducing Lync Mobile to the environment required cookie-based persistence to be configured on the HLB to provide session affinity to Lync mobile users. Because the session for each connected client was maintained only on the Front End Server they connected to, the client would always be required to connect to that same server. As such, cookie-based persistence was required to provide this affinity. In Lync Server 2013, the requirements for cookie-based persistence have been removed, including for Lync 2010 Mobile clients connecting to Lync Server 2013 servers. Lync Server 2013 Front End Servers will maintain session affinity for mobile clients; as such, source address affinity should be configured on the HLB instead of cookie-based persistence.